I can only tell you that for my 10yr old his units of humalog are of a ratio to carb counting, it varies during the day ie. 1u to 10g to 1 1/2u to 10g of carbs depending on time of day and type of carb. Remebering that he's growing and hitting puberty soon, his will vary significally to that of an adults. As for his intake of Levimer, even his is higher at 20u before bed than that of Fergus.
Each persons insulins needs varies, i can compare my son to other children and he is taking almost double, but it works for him. An idea of childrens requirements is take his basal amount and add his bolus the total should come close to weight in Kg, ie 20u Levimer plus average of Humalog 22u equals 42u and he weighs in about 43Kg, again each days food requirements differ, but its close. Not sure if this works for adults.
Your dosage does seem high, even for an adult, if your unhappy with the amount of insulin you take talk to your DN and have a go at carb counting.
Take care
Suzi x